Electrical connector



y 17, 1956 A. E. ANDERSON ELECTRICAL CONNECTOR Filed Nov. 19, 1952JNVENTOR. BY 4K5 finderson QMQAMALQ' ATTORNEY" ELECTRICAL CONNECTOR AlfE. Anderson, Milton, Mass.

Application November 19, 1952, Serial No. 321,417

4 Claims. (Cl. 339-47) This invention relates to an electricalconnector.

In general, the object of the present invention is to provide a noveland improved insulated electrical connector wherein the insulation isconstructed to cover the entire length of the connector to prevent thesame from being accidentally short-circuited, and wherein a portion ofthe insulation is particularly constructed to be automaticallycompressed or contracted when an electrical connection is made to asecond connector.

A further object of the present invention is to provide an improvedinsulated connector in which the contracting portion of the insulationwill retain its resiliency for a long period of time, and which will notcrack or wear out easily.

A still further object is to provide an insulated connector in which thecontracting portion thereof is constructed to contract or be compressedin a substantially straight, longitudinal direction to permit a similarconnector to make an electrical connection therewith.

With these general objects in view and such others as may hereinafterappear, the present invention consists in the insulated. electricalconnector and in the insulating member for such electrical connectorhereinafter described and particularly defined in the claims at the endof this specification.

In the drawings illustrating the preferred embodiment of the presentinvention:

Fig. 1 is a longitudinal sectional view showing two insulated metalconnectors operatively connected together;

Fig. 2 is an annular view of an insulating member provided with anexternal helical spring;

Fig. 3 is a similar view showing the insulating member provided with aninternal helical spring; and

Fig. 4 is a similar view showing the insulating member without a spring.

In accordance with the present invention, an electrical connector of thetype comprising an elongated body portion is provided with connectingmeans at its forward end adapted for cooperation with another electricalconnector to effect an electrical connection, and the body portion isprovided with an insulating sleeve enclosing the same and normallyextended beyond the connecting means of the connector. The insulatingsleeve is constructed to contract longitudinally and expose theaforesaid connecting means when pressure is applied to the end portionof the sleeve by the corresponding portion of the second connector whenthe electrical connection is being made.

Referring now to the drawing which illustrates a preferred embodiment ofthe invention, 10, 12 comprise identical connectors, each having atubular body portion to which cables 14, in are connected in accordancewith the usual practice. The body portion of each connector is providedwith fingers 13, 15 so arranged as to permit the two connectors to bemoved in a longitudinal direction into telescoping engagement when theconnection is made. In the illustrated embodiment of the invention, thefingers comprise semicircular elements of unequal dimensions, one finger13 having a smaller radius in cross section than 2,755,449 Fatented July17, 1956 its opposed finger 15 so that when the connection is made, thesmaller fingers fit within and slidingly engage the larger radiusfingers of the terminal members. Provision is also preferably made forlocking the fingers in their engaged position, and as herein shown,notched portions 26 are provided along the longitudinal edges ofadjacent fingers 15, and these notches are brought into engagement byimparting a slight twisting or rotary motion to the connectors, as willbe apparent from an inspection of Fig. 1.

While the illustrated form of connecting means is preferably provided atthe forward end of each electrical connector, it will be understood thatvarious other forms of connecting means may be employed including, forexample, that disclosed in the United States patent to Reynolds No.2,125,816, August 2, 1938.

In accordance with the present invention, the elongated connectors iii,12 are each provided with and enclosed within a protective insulatingsleeve indicated generally at 29. The rear portion of each sleeve ispreferably constructed to be substantially incompressible when theelectrical connection is being made and to have a portion 22 snuglyfitting about the cable end 14 and its connection to the rear of theconnector, and to have a thickened portion 23 embracing and snuglyfitted upon the rear of the connector itself to firmly frictionally holdthe sleeve upon the connector when the electrical connection is beingmade. The portion 24 of the sleeve extended forwardly from the thickenedportion 23 projects beyond the end of the connector and is sufiicientlythin and is molded of resilient material, such as rubber, in the form ofa helix to permit it to be collapsed or compressed to expose the endportion of the connector when the electrical connection is being madewith the cooperating connector. The forward end portion of the sleeve ispreferably provided with a rounded annular rim which affords awatertight seal between it and the correspondingly shaped rim of thesleeve upon the cooperating connector when the electrical connection ismade. It has been found in practice that the helical shape of theconvolutions in the forward portion of the sleeve contributes greatly toinsuring the compression of the convolutions in a direction lengthwiseof the connectors while maintaining the convolutions in the desiredaxial relationship to the connectors.

It may be readily observed from the description thus far that when thecooperating connectors are operatively connected together the contactingannular rims 28 may become disaligned, and consequently an imperfectseal between said connectors may result. The present novel rounded endsof the annular rims 23 eliminate the possibility of such imperfect sealsbeing formed. it will be observed that when the rounded ends ofcooperating connectors are pressed together, one end portion will rollupon the other and a firm Water-tight seal is constantly maintainedbetween said ends. Thus, a substantially perfect seal is always achievedwhen the connectors are connected. A further advantage of this novelfeature is that said connectors may be rapidly connected without regardto the alignment of the rims 28, and the user may always be assured of aproper, satisfactory seal.

In the modified form of the invention illustrated in Fig. 2, an externalhelical spring 37 is mounted to encircle the helically corrugatedportion 24 of the sleeve 20 and increases the resistance of the sleeveto compression, thereby contributing to the maintenance of a watertightcontact between the cooperating rims of the two sleeves when theelectrical connection is made. In order to secure the spring 37 inoperative position, the annular rims 28 are provided with externalannular grooves 38 as shown. The compressive force of the aforementionedhelical springs may be varied according to the size and manner in whichthe present connector is utilized in order 2,755,449 H H t H V to assurea completely insulated and efficient joint between said connectedconnectors.

In another modified form of the invention as illustrated in Fig. 3, inorder to assure an even more efficient joint between cooperatingconnectors, a helical spring 34 is provided to fit internally withinsaid sleeve to further increase the resiliency and resistance ofcompression of the helical portion of the sleeve. In order to secure theinternally positioned spring within the corrugated portion of thesleeve, the annular rim 23 is provided with an annular groove 35 intowhich the end of the helical spring may be fitted and securely retained.

As a result of the provision of the springs in the constructionsillustrated in Figs. 2 and 3, the rim portions 23 of the two cooperatingsleeves are pressed together with increased force preventing theinsulating sleeves from being pulled accidentally apart to expose themetal contacting elements of the connected connectors or to allowmoisture to enter.

It will be observed that the present invention provides a connectorhaving superior dimensional stability, is longer wearing and permitshelical springs to be used either externally or internally to therebyincrease the pressure exerted by one insulated connector against acooperating insulated connector when the same are operatively connectedtogether to assure a fuliy insulated electrical connection between thesame.

In practice, the sleeve member 20 is preferably of rubber and the entiresleeve molded into the shape disclosed in the drawings. Thus, thepresent sleeves are relatively inexpensive to manufacture and are highlyefficient for use with numerous types of electrical connectors.

While the preferred embodiments of the present invention have beenherein illustrated and described, it will be understood that theinvention may be embodied in other forms within the scope of thefollowing claims.

Having thus described the invention, what is claimed 1. An electricalconnector comprising an elongated body portion provided with a forwardterminal portion constructed for telescopic engagement with acorresponding terminal of a second connector, said body portion beingprovided with an elongated resilient insulating sleeve having its rearportion snugly fitting on the rear of the body portion and having itsforward end flexible and corrugated in helical form, the forward end ofthe sleeve normally projecting beyond the forward end of the connectorand the helical structure of the sleeve facilitating an even compressionof the sleeve to expose the forward end of the connector when anelectrical connection is made, said helically formedend being molded toprovide fixed corrugations when the sleeve is extended and capable ofbeing uniformly compressed when a connection is made.

2. An electrical connector as defined in claim 1 wherein the helicallycorrugated sleeve is provided with a spring surrounding the sleeve withindividual convolutions of the spring disposed within the bottom of thehelical corrugations.

3. An electrical connector comprising an elongated body portion providedwith a forward terminal portion constructed for telescopic engagementwith the corresponding terminal of a second connector, said body portionbeing provided with an elongated resilient insulating sleeve having itsrear portion relatively thick and having a shoulder on the forward endthereof, and having its forward end substantially thinner than the rearportion and corrugated in helical form, the forward end of said helicalportion of the sleeve being provided with an annular end lip having arear shoulder and a rounded forward portion and a coil spring disposedaround said helical portion of the sleeve with individual convolutionsof the spring disposed in the bottom of the helical convolutions andwith the rear and forward convolutions of the spring engaging theshoulder portions of the rear portion of the sleeve and the forwardannular end portion, respectively, said helically formed end beingmolded to provide fixed corrugations when the sleeve is extended andcapable of being uniformly compressed when a connection is made.

4. An electrical connector as defined in claim 1 wherein the helicallycorrugated forward portion of the sleeve is provided with a coil springwithin the same and with individual convolutions of the spring disposedwithin individual corrugations of the sleeve.

References Cited in the file of this patent UNITED STATES PATENTS F--"in' ma

